this post was submitted on 24 May 2025
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cat /proc/sys/kernel/random/uuid [I ❤️ Linux] (feddit.org)
submitted 2 weeks ago* (last edited 1 week ago) by A_norny_mousse@feddit.org to c/linux@programming.dev
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That's all. I just found this in a random script. Generates a random UUID every time it's called. I didn't know.

Of course I can also use uuidgen or pipe /dev/(u)random into something to get a random alphanumeric string - but this is built right into the kernel!

In /proc/sys/kernel/random/, there's also boot_id which ~~seems to do the same~~ is static, and some tweakable parameters.

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[–] victorz@lemmy.world 9 points 2 weeks ago* (last edited 1 week ago) (4 children) 
cat /proc/sys/kernel/random/uuid > /dev/null
[–] henfredemars@infosec.pub 3 points 2 weeks ago (1 children)

The information will be evenly distributed upon its surface and some believe one day it will be be radiated back out into the rest of the system.

[–] Hamartiogonic@sopuli.xyz 2 points 2 weeks ago

That's a horrifying concept. Better not think about it.

[–] A_norny_mousse@feddit.org 3 points 1 week ago* (last edited 1 week ago)

while :; do cat /proc/sys/kernel/random/uuid > /dev/null; done

edit: on all cores for maximum "efficiency"

[–] Hamartiogonic@sopuli.xyz 1 points 2 weeks ago (3 children)

That reminds me of the CPU stress test I ran many years ago.

dd if=/dev/random of=/dev/null

If you have 8 cores, just open 8 terminals, and run that code in each of them.

[–] YerbaYerba@lemm.ee 4 points 2 weeks ago

/dev/urandom should stress the CPU more. /dev/random can be entropy limited

[–] lime@feddit.nu 3 points 2 weeks ago* (last edited 2 weeks ago) (1 children) 
for i in {1..n}  # where n == number of cores
do
  dd if=/dev/urandom of=/dev/null &
done

# to stop:
jobs -p | xargs kill
[–] Hamartiogonic@sopuli.xyz 1 points 1 week ago (1 children)

Oh yeah. This looks like a much better way to do it. My solution is pretty bare bones by comparison.

[–] lime@feddit.nu 1 points 1 week ago

the advantage of yours is that you can actually see the performance number afterwards.

[–] victorz@lemmy.world 2 points 1 week ago (1 children)

Can you guarantee that each process will run on its own core?

[–] Hamartiogonic@sopuli.xyz 2 points 1 week ago

Absolutely not, quite the opposite actually. However, the end result is close to 100% CPU load, which is good enough for some purposes. Let’s say you want to test the performance of your CPU cooler, or overclock stability, this should good enough. There are also dedicated tools for people with more advanced needs.